What is PPAP and why it matters
PPAP stands for Production Part Approval Process. It is a standardised quality-approval process used in the global automotive industry to demonstrate that a supplier has all the engineering design records and specification requirements properly understood and that the production process can consistently produce parts that meet these requirements during an actual production run.
PPAP was developed by the Automotive Industry Action Group (AIAG) and is published as the AIAG PPAP 4th Edition (2006, reaffirmed 2018). It applies to all parts supplied to participating OEMs (Stellantis, Ford, GM, and their Indian equivalents - Maruti, Tata, M&M, Hero, Bajaj, TVS, Royal Enfield).
For Indian Tier-1 and Tier-2 suppliers, PPAP submission is mandatory for any new part, any change in part design, any change in manufacturing location, and (typically) once every two years for ongoing parts. Submission rejection means the part cannot be supplied to the OEM. PPAP is not optional - it is the gating compliance for being a Tier-1 supplier.
The 18 PPAP elements
AIAG PPAP defines 18 specific elements. The customer (OEM) determines which combination to submit, based on the chosen submission level (1-5).
- 1. Design Records - the customer-approved design drawings, including all dimensions, tolerances, notes, and reference standards.
- 2. Engineering Change Documents - all engineering change notices (ECNs) since the previous PPAP, with customer approval.
- 3. Customer Engineering Approval - written approval from customer's engineering team for any deviations from drawing.
- 4. Design FMEA (DFMEA) - the design failure mode and effects analysis, owned by the design authority (the customer in most Tier-1 supplies).
- 5. Process Flow Diagrams - the entire manufacturing process flow from raw material receipt to dispatch.
- 6. Process FMEA (PFMEA) - the process failure mode and effects analysis, owned by the supplier.
- 7. Control Plan - the document that specifies how each characteristic of the part is controlled during production.
- 8. Measurement System Analysis (MSA) - statistical study (Gauge R&R) showing the measurement system is capable.
- 9. Dimensional Results - measurement of all dimensions for the production sample, against drawing tolerances.
- 10. Material/Performance Test Results - chemical composition, mechanical properties, performance test results per drawing specifications.
- 11. Initial Process Studies - statistical capability studies (Cpk, Ppk) on all special characteristics.
- 12. Qualified Laboratory Documentation - NABL or equivalent accreditation certificates for the labs performing the measurements.
- 13. Appearance Approval Report (AAR) - for parts with appearance requirements (paint, plating, decals).
- 14. Sample Production Parts - actual parts from the production run, retained for reference.
- 15. Master Sample - a single PPAP-approved master sample, retained by supplier and customer.
- 16. Checking Aids - any custom gauges, fixtures, or templates used to verify the part.
- 17. Customer-Specific Requirements - any additional documents the customer requires beyond the standard PPAP.
- 18. Part Submission Warrant (PSW) - the cover sheet of the PPAP submission, signed by an authorised quality engineer at the supplier.
PPAP submission levels (1 through 5)
The customer specifies which submission level applies. Each level dictates which of the 18 elements are sent to the customer and which are retained on file at the supplier:
- Level 1: Only PSW submitted; for parts where the customer trusts the supplier completely (typically catalog parts or where capacity is small).
- Level 2: PSW + product samples + limited supporting data submitted; rest on file.
- Level 3 (most common for new parts): PSW + product samples + complete supporting data submitted. This is the default for new part introductions to most Indian OEMs.
- Level 4: PSW + other requirements as defined by the customer; varies widely.
- Level 5: PSW + product samples + complete supporting data available at supplier's location for customer review (no submission, but auditable).
The Part Submission Warrant (PSW)
The PSW is the single-page (or two-page) form that sits on top of the PPAP submission. It summarises:
- Part number, name, and engineering change level.
- Reason for submission (initial submission, engineering change, material change, location change, etc.).
- Submission level (1-5).
- Production rate during the trial run (pieces per hour).
- Authorisation: signature, name, title, date of the supplier quality engineer.
- Customer disposition box (filled by customer after review): Approved, Interim Approval, Rejected.
Process Flow Diagram - element 5 done right
The process flow diagram shows every step from raw material receipt to dispatch, in sequence, with each operation numbered. It is not a fancy chart - it is a list of operations with a clear flow.
What auditors look for:
- All operations numbered consecutively.
- All inputs (raw materials, sub-assemblies) shown entering the flow.
- All operations include the resource (machine, station, or area).
- Any sub-contracted operations explicitly marked.
- Inspection points clearly marked (incoming, in-process, final).
- Material handling steps (storage, transport) included.
PFMEA - element 6 done right
Process FMEA identifies how each step in the process can fail, what the effect of the failure is, and what controls are in place to prevent or detect it. It is owned by the supplier (DFMEA is owned by the customer's design authority).
A row in the PFMEA contains:
- Process step (from the process flow diagram).
- Potential failure mode at that step.
- Effect of failure (on customer).
- Severity rating (1-10).
- Potential cause of failure.
- Occurrence rating (1-10).
- Current process controls.
- Detection rating (1-10).
- Risk Priority Number (RPN) = Severity × Occurrence × Detection.
- Recommended action if RPN exceeds threshold.
Control Plan - element 7 done right
The control plan is the most-audited document in a PPAP submission. It specifies how each special characteristic of the part is controlled during production.
Each row in the control plan covers:
- Part characteristic (dimension or property being controlled).
- Operation number and machine.
- Specification and tolerance.
- Measurement method and instrument.
- Frequency of measurement (e.g., 'every 100 pieces' or 'first piece + every hour').
- Sample size.
- Control method (SPC, 100% inspection, visual).
- Reaction plan if out of specification.
Initial Process Studies (Cpk and Ppk) - element 11
Capability studies prove the production process can consistently produce parts within tolerance. Two indices are required:
- Pp / Ppk: process performance during the production trial run. Computed using actual measurement data from the trial.
- Cp / Cpk: process capability for ongoing production, used after the process is stable.
How ERP automates PPAP
PPAP is document-heavy but the documents are derived from data the ERP already has. ERPDrive's PPAP module auto-generates:
- Process flow diagram from the routing.
- Control plan template from the inspection plan.
- Dimensional results from QC measurements logged at each operation.
- Initial process study (Cp/Cpk) computed from the production-trial data.
- PSW pre-populated with part details, change level, submission level.
Frequently Asked Questions
What is PPAP in automotive manufacturing?
PPAP stands for Production Part Approval Process. It is a standardised quality-approval process used in the global automotive industry to demonstrate that a supplier can consistently produce parts that meet engineering requirements during actual production. PPAP is mandatory for any new part, any design change, any manufacturing location change, and typically every 2 years for ongoing parts. The AIAG PPAP 4th edition (2006, reaffirmed 2018) defines the standard.
What are the 18 elements of PPAP?
Design Records, Engineering Change Documents, Customer Engineering Approval, Design FMEA, Process Flow Diagram, Process FMEA, Control Plan, Measurement System Analysis (MSA), Dimensional Results, Material/Performance Test Results, Initial Process Studies (Cpk/Ppk), Qualified Laboratory Documentation, Appearance Approval Report, Sample Production Parts, Master Sample, Checking Aids, Customer-Specific Requirements, and Part Submission Warrant (PSW).
What is a PSW in PPAP?
PSW stands for Part Submission Warrant. It is the cover sheet of a PPAP submission that summarises the part number, change level, reason for submission, submission level (1-5), production trial rate, and the supplier quality engineer's authorisation. The customer's quality engineer signs the disposition box (Approved, Interim Approval, or Rejected) and returns the PSW to the supplier. Without an approved PSW, the supplier cannot ship the part.
What is the most common PPAP submission level?
Level 3 is the most common for new parts to most Indian OEMs (Maruti, Tata, M&M, Hero). Level 3 requires PSW plus product samples plus the complete set of supporting documents submitted to the customer. Levels 1-2 are used for established suppliers with high trust; Level 5 keeps everything on file at the supplier with no submission but full audit accessibility.
What Cpk/Ppk values does PPAP require?
For special characteristics in new parts (PPAP), Ppk greater than 1.67 is typically required. For ongoing production, Cpk greater than 1.33 is typically required. If Ppk is below 1.33, the OEM usually requires 100% inspection of that characteristic until the process is improved. PPAP requires the initial process study to use 300 consecutive pieces from a single production trial run.
How long does PPAP preparation take for a new part?
First-time PPAP for a new part typically takes 8-14 weeks for an Indian Tier-1 supplier, depending on part complexity and the supplier's document discipline. Suppliers with strong ERP-driven document management can complete PPAP in 4-6 weeks. The bottleneck is rarely the engineering work - it is compiling 18 separate documents from data spread across multiple spreadsheets and people.
What is the difference between DFMEA and PFMEA?
DFMEA (Design FMEA) analyses how the part design can fail and is owned by the design authority - typically the OEM. PFMEA (Process FMEA) analyses how the manufacturing process can fail and is owned by the supplier. Both are part of PPAP. The two FMEAs should be linked: a failure mode in PFMEA may reference a failure effect that originates in DFMEA. PFMEA is more dynamic - it should be updated whenever the process changes or new failure modes are observed.
Sources & References
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